Light therapy: Not just for seasonal depression?

A new study suggests that light therapy might not just be for those affected by seasonal depression and could be used to treat major depressive disorder.

The study was published on Wednesday in the journal JAMA Psychiatry, and found that light therapy–either by itself or coupled with antidepressant medication–is an effective treatment for adults with major depressive disorder.

Light therapy is generally used to treat patients with seasonal affective disorder. Although seasonal affective disorder can affect people in the summer, it’s most commonly associated with late autumn and winter, and it’s thought to be caused by a lack of light.

To make up for a lack of light, people who find themselves with winter depression often turn to conventional Full Spectrum light boxes–more commonly known as light boxes–to make them feel better; the theory behind them is that they’re able to effectively replicate sunshine. And that’s light therapy. Researchers claim that this light causes a chemical reaction in the brain that helps ease the symptoms that come with depression.

The study that’s claiming that the effects of light therapy go beyond seasonal affective disorder conducted a trial with 122 adult participants (between the ages of 19 and 60), who were recruited from psychiatric outpatient clinics in Toronto and Vancouver. All 122 participants were diagnosed with major depressive disorder.

Major depressive disorder is the second-ranked cause of disability worldwide, and it’s estimated that it affects at least 5% of the population, causing a decrease in quality of life and increase in mortality.

The participants were randomly separated into four groups: light therapy and placebo antidepressants, placebo light therapy and antidepressants, a combination of light therapy and antidepressants, and a combination of placebo light therapy and placebo antidepressants.

Participants were told to use their fluorescent light box for 30 minutes in the morning, and at the end of the trial, they were assessed for depression using a diagnostic questionnaire. The scores were compared to baseline measurements. The study found that 55% of the participants using either only light therapy or only antidepressants (Prozac) saw a lift in their depression, while 76% of participants using both light therapy and antidepressants saw a lift in their depression.

While major depressive disorder is generally treated with antidepressants and psychotherapy–both which produce low remission rates–Dr. Raymond Lam, the leading author on the study and professor of psychiatry at the University of British Columbia, stated that the trial was performed during all of the year’s seasons, suggesting that light therapy could be used to treat symptoms that extend beyond seasonal affective disorder.

Although he admits that more studies need to be conducted to confirm the trial’s results, he states that the trial “really does show that light can be used to treat different types of depression, not just ‘winter depression.'”

Chief of the Brain Sciences Program at Toronto’s Sunnybrook Hospital, Dr. Anthony Levitt, stated that light therapy is an “innocuous” treatment for depression–meaning that it isn’t harmful. He also stated that patients with certain disorders, such as bipolar disorder, should be cautioned against it.

Ken Porter, a program manager with the Mood Disorders Society of Canada, finds the results to be encouraging.

“Any study that encourages treatment is worthwhile. We’ve seen individuals who’ve talked about the success of light therapy in the past, and having a study that confirms their feelings is quite beneficial.”